in 50322dff ("MEDIUM: server: add init-state"), some examples on how to
use init-state server keyword were added alongside with the keyword
documentation.
However, as reported by Nick Ramirez, there was an error because the
example that stated that haproxy will pass the traffic to the server after
3 successful health checks used the "init-state down" instead of the
"init-state fully-down". Thus the behavior wouldn't match what the
comment said (only 1 successful health check was required).
Here we fix the example in itself to match with the comment. Also the
following example ("# or") was also affected, but it is kind of
redundant as the main purpose of the examples are to illustrate the
feature in itself and not how to use server-template directive, so we
remove it.
This should be backported in 3.1 with 50322dff
When "recv-only" keyword is added on a stick table declaration (in peers
or proxy section), haproxy considers that the table is only used for
data retrieval from a remote location and not used to perform local
updates. As such, it enables the retrieval of local-only values such
as conn_cur that are ignored by default. This can be useful in some
contexts where we want to know about local-values such are conn_cur
from a remote peer.
To do this, add stktable struct flags which default to NONE and enable
the RECV_ONLY flag on the table then "recv-only" keyword is found in the
table declaration. Then, when in peer_treat_updatemsg(), when handling
table updates, don't ignore data updates for local-only values if the flag
is set.
Patref:set(key, val[, force]) takes optional "force" parameter (defaults
to false) to force the entry to be created if it doesn't already exist
To retrieve the value, lua_tointeger() was used in place of
lua_toboolean(), and because of that force is not enabled if "true"
is passed as parameter (only numbers were recognized) despite the
documentation mentioning that "force" is a boolean.
To fix the issue, we replace lua_tointeger by lua_toboolean.
Also, the doc was updated to rename "bool" to "boolean" for the "force"
parameter to stay consistent with historical naming in the file.
No backport needed unless 9ee37de5c ("MINOR: hlua_fcn: add Patref:set()")
is.
Patref:set() can achieve the same thing as core.set_map()
Patref:add() can achieve the same thing as core.add_acl()
Patref:del() can achieve the same thing as core.del_map() and
core.del_acl()
As a bonus, Patref:{set,add} are more efficient than their core
legacy equivalent, because they don't require systematic pattern
reference lookup for each individual operation.
Let's mention that in the doc to encourage Patref methods adoption.
Just like we did for server events, in this patch we expose the PAT_REF
event family (see "MINOR: event_hdl: add PAT_REF events") in Lua.
Unlike server events, Patref events don't provide additional event data,
and the registration can only take place from a Patref object (ie: not
globally).
Thanks to this commit it now becomes possible to trigger actions when
updates are performed on a map (or acl list) being monitor, without
the need to loop or use inefficient workarounds.
There is no cli equivalent for this one. It is similar to Patref:add()
excepts thay it takes a table as parameter (for acl: table of keys, for
maps: table of keys:values). The goal is to add multiple entries at once
to limit locking time to the strict minimum. It is recommended to use this
one over Patref:add() when adding multiple entries at once.
Just like "set map" on the cli, the Patref:set() method (only relevant
for maps) can be used to modify an existing entry's value in the pattern
reference pointed to by the Lua Patref object. Lookup is performed on the
key. The update will target the live pattern reference version, unless
Patref:prepare() is ongoing.
Just like "del map" and "del acl" on the cli, the Patref:del() method can
be used to delete an existing entry in the pattern reference pointed to
by the Lua Patref object. The update will target the live pattern
reference version, unless Patref:prepare() is ongoing.
Just like "add map" and "add acl" on the cli, the Patref:add() method can
be used to add a new entry to the pattern reference pointed to by the
Lua Patref object. The update will target the live pattern reference
version, unless Patref:prepare() is ongoing.
If Patref:commit() was used and the new version (generation) isn't going
to be committed, calling Patref:giveup() will allow allocated resources
to be freed and reused. It is a good habit to call this if commit()
isn't called after a prepare().
It is a special Lua Patref method: it bypasses the commit/prepare logic
and purges the whole pattern reference items pointed to by Patref Lua
object (all versions, not just the current one). It doesn't have a cli
equivalent: it leverages pat_ref_purge_range().
Just like the "prepare map" or "prepare acl" on the cli, but for Lua:
it leverages the pattern API to create a subset (ie: a new generation id)
that will automatically be used as target for following Patref operations
(add/set/del...) until the "commit" method is invoked to atomically push
the pending updates.
commit() method may be used to commit pending updates on the local patref
object:
hlua_patref flags were added:
HLUA_PATREF_FL_GEN means the patref object has been updated
and it is associated to a new revision (curr_gen) in order to prepare
and commit the pending updates.
upon commit, the pattern API is leveraged with curr_gen as revision to
commit new object items. Once commit is performed, previous (pending)
revisions that are older than the committed one are cleaned up (similar
to what's done with commit on the cli). Also, Patref function APIs now
take into account curr_gen to perform lookups.
patref object may now leverage index and pair methamethods to list and
access patref elements at a specific index (=key)
Also, patref:is_map() method may be used to know if the patref stores acl
(key only) or map-style (key:value) patterns.
core.get_patref() method may be used to get a reference to a pattern
object (pat_ref struct which is used for maps and acl storage) from
Lua by providing the reference name (filename for files, or prefix+name
for opt or virtual pattern references).
Lua documentation was updated.
The "421" status can now be specified on retry-on directives. PR_RE_* flags
were updated to remains sorted.
This patch should fix the issue #2794. It is quite simple so it may safely
be backported to 3.1 if necessary.
Released version 3.1.0 with the following main changes :
- BUG/MAJOR: mux-h1: Properly handle wrapping on obuf when dumping the first-line
- BUILD: activity/memprofile: fix a build warning in the posix_memalign handler
- BUG/MINOR: quic: Avoid BUG_ON() on ->on_pkt_lost() BBR callback call
- CI: update to the latest AWS-LC version
- CI: update to the latest WolfSSL version
- DOC: ot: mention planned deprecation of the OT filter
- Revert "CI: update to the latest WolfSSL version"
- CI: github: add a WolfSSL job which tries the latest version
- BUILD: systemd: fix usage of reserved name "sun" in the address field
- BUILD: init: use the more portable FD_CLOEXEC for /dev/null
- CI: github: improve the Wolfssl job
- CI: github: improve the AWS-LC job
- BUG/MINOR: mux-quic: fix show quic report of QCS prepared bytes
- BUG/MEDIUM: quic: fix sending performance due to qc_prep_pkts() return
- MINOR: mux-quic: use sched call time for pacing
- CI: github: allow to run the Illumos job manually
- BUILD: tcp_sample: var_fc_counter defined but not used
- CI: github: add 'workflow_dispatch' on remaining build jobs
- DOC: config: refine a little bit the text on QUIC pacing
- MINOR: proto_sockpair: send_fd_uxst: init iobuf, cmsghdr, cmsgbuf to zeros
- MINOR: startup: rename on_new_child_failure to mworker_on_new_child_failure
- REORG: startup: move on_new_child_failure in mworker.c
- MINOR: startup: prefix prepare_master and run_master with mworker_*
- REORG: startup: move mworker_prepare_master in mworker.c
- MINOR: startup: keep updating verbosity modes only in haproxy.c
- REORG: startup: move mworker_run_master and mworker_loop in mworker.c
- REORG: startup: move mworker_reexec and mworker_reload in mworker.c
- MINOR: startup: prefix apply_master_worker_mode with mworker_*
- REORG: startup: move mworker_apply_master_worker_mode in mworker.c
- MINOR: cfgparse-quic: strengthen quic-cc-algo parsing
- BUG/MAJOR: quic: fix wrong packet building due to already acked frames
- DEV: lags/show-sess-to-flags: Properly handle fd state on server side
- BUG/MEDIUM: http-ana: Don't release too early the L7 buffer
- MINOR: quic: make bbr consider the max window size setting
- DOC: quic: Amend the pacing information about BBR.
- BUG/MEDIUM: quic: prevent EMSGSIZE with GSO for larger bufsize
- MINOR: cli: Add a "help" keyword to show sess
- MINOR: cli/quic: Add a "help" keyword to show quic
- DOC: management: mention "show sess help" and "show quic help"
- DOC: install: update the list of supported versions
- MINOR: version: mention that 3.1 is stable now
The QUIC pacing options changed a few times during their development.
For example the unit is now in datagrams not bytes. Also a few
sentences were slightly ambiguous so let's reword this.
No backport is needed.
Miroslav mentioned below that he's currently working on an OpenTelemetry
replacement for the OpenTracing filter since OpenTracing itself is no
longer maintained nor supported:
https://github.com/haproxy/haproxy/issues/2782#issuecomment-2493576327
Given that he aims for 3.2, let's already settle on an upcoming deprecation
of the filter for 3.3 with a removal for 3.5. This will leave time to finish
the development and permit users to switch smoothly. At this point no warning
is emitted (since the users have no alternative) but better mention this plan
in the doc to make them aware of future changes.
Released version 3.1-dev14 with the following main changes :
- MINOR: acl: export find_acl_default()
- MINOR: sample: extend the "when" converter to support an ACL
- MINOR: cfgparse: parse tune.{rcvbuf,sndbuf}.{client,server} as sizes
- MINOR: cfgparse: parse tune.{rcvbuf,sndbuf}.{frontend,backend} as sizes
- MINOR: cfgparse: parse tune.pipesize as a size
- MINOR: cfgparse: parse tune.recv_enough as a size
- MINOR: cfgparse: parse tune.bufsize as a size
- MINOR: cfgparse: parse tune.bufsize.small as a size
- REGTESTS: silence the "log format ignored" warnings
- REGTESTS: silence warning "previous 'http-response' action is final"
- REGTESTS: make the unit explicit for very short timeouts
- REGTESTS: silence warnings about content-type being ignored
- REGTESTS: remove a duplicate "option httpslog" in the defaults section
- REGTESTS: silence warning "L6 sample fetches ignored" in cond_set_var
- REGTESTS: add missing timeouts to 30 tests
- REGTESTS: only use tune.ssl.default-dh-param when not using AWS-LC
- REGTESTS: enable -dW on almost all tests to fail on warnings
- MEDIUM: config: warn on unitless timeouts < 100 ms
- MINOR: tools: make parse_size_err() support 32/64 bits
- MINOR: ring: support unit suffixes in the size
- MINOR: cfgparse-global: parse options to allow non std keywords in discovery mode
- BUG/MINOR: mworker-prog: don't warn about deprecated section with expose-deprecated-directives
- MINOR: cli: make "show env" accessible via master CLI without enabling debug
- MINOR: config: show HAPROXY_BRANCH in "show env" output
- MINOR: http-ana: Add option to keep query-string on a localtion-based redirect
- MINOR: http-ana: Add support for "set-cookie-fmt" option to redirect rules
- MINOR: agent-check: Be able to set absolute weight via an agent
- MINOR: stream: Add an option to "show sess" command to dump the captured URI
- DOC: config: A a space before ':' for {bs,fs}.aborted and {bs,fs}.rst_code
- DOC: config: Fix a typo in "1.3.1. The Request line"
- MINOR: http: Add support for HTTP 414/431 status codes
- DEV: phash: Update 414 and 431 status codes to phash
- MINIR: mux-h1: Return 414 or 431 when appropriate
- BUG/MINOR: http_ana: Report -1 for %Tr for invalid response only
- DOC: config: Slightly improve the %Tr documentation
- DOC: config: Move wait_end in section about internal samples
- DOC: config: Move fs.* and bs.* in section about L5 samples
- MINOR: stats-file: add the filename in the warning
- MEDIUM: stats-file: explicitely ignore comments starting by //
- DOC: quic: rename max-window-size as with default prefix
- MINOR: mux-quic: add missing values for show flags
- MINOR: quic: simplify qc_prep_pkts() exit path
- MINOR: quic: support a max number of built packet per send iteration
- MINOR: quic: extend qc_send_mux() return type with a dedicated enum
- MINOR: quic: define quic_pacing module
- MINOR: quic/pacing: implement quic_pacer engine
- MINOR: quic/pacing: support pacing emission on quic_conn layer
- MINOR: quic/pacing: add burst support
- MINOR: mux-quic: define a tx STREAM frame list member
- MINOR: mux-quic: encapsulate QCC tasklet wakeup
- MAJOR: mux-quic: support pacing emission
- MINOR: quic: use dynamic cc_algo on bind_conf
- MINOR: quic: extend quic-cc-algo optional parameters
- MEDIUM: quic: define cubic-pacing congestion algorithm
- MINOR: mux_quic/pacing: display pacing info on show quic
- MEDIUM: stats-file: silently ignore be/fe mistmatch
- REGTESTS: use -dW by default on every reg-tests
- DOC: lua: fix yield-dependent methods expected contexts
- DOC: sched: add missing scheduler API documentation for tasklet_wakeup_after()
- DOC: sched: document the missing TASK_F_UEVT* flags
- CLEANUP: tinfo: move sched_*_date/*_mono_time to the thread-local area
- MINOR: stream: don't update s->lat_time when the wakeup date is not set
- MINOR: tinfo/clock: turn sched_call_date to 64-bits
- MINOR: sched: add TASK_F_WANTS_TIME to make the scheduler update the call date
- MINOR: tools: add new macro DEFZERO to provide a default zero argument
- MINOR: tasklet: make the low-level tasklet API take a flag
- MINOR: tasklet: support an optional set of wakeup flags to tasklet_wakeup_on()
- DOC: configuration: explain the rules regarding spaces in arguments
- DOC: configuration: explain quotes and spaces in conditional blocks
- DOC: configuration: wrap long line for "strstr()" conditional expression
- BUG/MINOR: http-ana: Adjust the server status before the L7 retries
- MINOR: http-fetch: Add an option to 'query" to get the QS with the '?'
- BUG/MINOR: cfgparse-quic: fix renaming of max-window-size
- MEDIUM: mworker: remove USE_SYSTEMD requirement for -Ws
- CI: vtest: temporarily build from the sd-notify PR
- MINOR: systemd: replace SOCK_CLOEXEC by fcntl call to FD_CLOEXEC
- BUILD: makefile: make ERR apply to build options as well
- MINOR: startup: set HAPROXY_LOCALPEER only once
- DOC: configuration: update "Environment variables" chapter
- DOC: config: indent the list of environment variables
- OPTION: map/hlua: make core.set_map() lookup more efficient
- REGTESTS: switch to -Ws for master-worker reg-tests
- REGTESTS: disable temporarly mworker test on OSX
- MINOR: quic: Add the congestion window initial value to QUIC path
- MINOR: window_filter: Implement windowed filter (only max)
- MINOR: quic: implement delivery rate sampling algorithm
- MINOR: quic: implement BBR congestion control algorithm for QUIC
- MINOR: quic: quic_cc modifications to support BBR
- MINOR: quic: quic_loss modifications to support BBR
- MINOR: quic: RX part modifications to support BBR
- MINOR: quic: TX part modifications to support BBR.
- MINOR: quic: add "bbr" new "quic-cc-algo" option
- BUG/MEDIUM: mux-h2: Increase max number of headers when encoding HEADERS frames
- BUG/MEDIUM: mux-h2: Check the number of headers in HEADERS frame after decoding
- BUG/MEDIUM: h3: Properly limit the number of headers received
- BUG/MEDIUM: h3: Increase max number of headers when sending headers
- DOC: config: Improve documentation of tune.http.maxhdr directive
- DOC: management: Clearly state "show errors" only reports malformed H1 messages
- BUILD: makefile: build flags.c before haproxy to speed up the build
- BUILD: makefile: reorder object files by build time
- MINOR: config: Improve warnings on misplaced rules by adding an optional arg
- CLEANUP: cfgparse: Add direction in functions name that warn on misplaced rules
- MINOR: cfgparse: Emit a warning for misplaced "tcp-response content" rules
- BUG/MINOR: cfgparse-quic: fix bbr initialization
- MINOR: cfgparse-quic: activate pacing only via burst argument
- MINOR: quic: Useless rate sample member initialization
- BUG/MINOR: cfgparse-quic: fix warning for cc-aglo with 0 burst
- MINOR: quic: support pacing for newreno and nocc
- BUG/MINOR: quic: Missing application limitations tracking for BBR
- MINOR: cfgparse-global: add cfg_parse_global_chroot
- MINOR: cfgparse-global: add more checks for "chroot" argument
- BUG/MINOR: startup: fix UAF when set the default for log_tag
- MINOR: capabilities: rename program_name argument to progname
- MINOR: startup: use global progname variable
- MINOR: cfgparse-global: add cfg_parse_global_localpeer
- BUG/MINOR: config: allow to check HAPROXY_LOCALPEER in config
- BUG/MINOR: startup: init_early: remove obsolete comment
- BUG/MEDIUM: debug: don't set the STUCK flag from debug_handler()
- BUG/MEDIUM: wdt: fix the stuck detection for warnings
- BUG/MINOR: activity/memprofile: reinitialize the free calls on DSO summary
- MINOR: activity/memprofile: offer a function to unregister stale info
- BUG/MEDIUM: pools/memprofile: always clean stale pool info on pool_destroy()
- MINOR: activity: better report nil than ffff in unknown callers
- CLEANUP: activity: better use a mask to tests freeing methods
- MINOR: activity/memprofile: also monitor strdup() activity
- MINOR: activity/memprofile: monitor non-portable calls as well
- MINOR: activity: interrupt the show profile dump more often
- MINOR: tools: resolve main() only once in resolve_sym_name()
- MINOR: tools: add a new function "resolve_dso_name" to find a symbol's DSO
- MINOR: activity/memprofile: use resolve_dso_name() for the DSO summary
- REGTESTS: relax strerror matching to avoid a failure on libmusl
- REGTESTS: don't rely on the base64 utility when openssl base64 is already used
This fixes the commit d6ccd1738b
("MINOR: startup: set HAPROXY_LOCALPEER only once"). HAPROXY_LOCALPEER could
be checked in the configuration to set some servers settings or listeners. So,
we need to set it just before we read the configuration at the second time.
Let's mark HAPROXY_LOCALPEER as "usable" in the configuration in the related
documentation chapter.
This should not be backported, as related to the latest master-worker
refactoring.
Recently, pacing support was added for cubic congestion algorithm. This
was activated by using the new token "cubic-pacing" on quic-cc-algo.
Furthermore, it was possible to define a burst size with a new
parameters after congestion token between parenthesis.
This configuration is not oblivious to users. In particular, it can
cause to easily forgot to tweak burst size, which can dramatically
impact performance.
Simplify this by removing the extra "-pacing" suffix. Now, pacing will
be activated solely based on the burst parameter. If 0, burst is
considered as infinite and no pacing will be used. Pacing will be
activating for any positive burst. This better reflects the link between
pacing and burst and its importance.
Note that for the moment, if burst is specified, it will be ignored with
a warning for algorithm outside of cubic.
This is not a breaking change as pacing support was implemented in the
current dev version.
For now, only the H1 multiplexer is able to capture malformed messages. So
it is better to update the management guide accordingly to avoid any
confusion.
The description was inproved to clrealy mentionned it is applied on received
requests and responses. In addition, a comment was added about HTTP/2 and
HTTP/3 limitation when messages are encoded to be sent.
Add this new "bbr" option to the list of the congestion control algorithms which
may be set by "quic-cc-algo" setting.
This new algorithm is considered as experimental and may be enabled only if
"expose-experimental-directive" is set.
Also update the documentation for this new setting.
In the doc our lists are indented but for any reason this one was not,
making it harder to visually delimit. Let's just indent it. No need to
backport this, it's totally cosmetic and would need adaptations since
it was recently touched.
There are some variables, which are set by HAProxy process (HAPROXY_*). Some
of them are handy to check or to redefine in the configuration, in order to
create conditional blocks and make the configuration more flexible. But it
wasn't clear in the documentation, which variables are really safe and usefull
to redefine and which ones could be only read via "show env" output.
Latest changes in master-worker architecture makes the existed description even
more confusing.
So let's sort all HAPROXY_* variables to four categories and let's also mark
explicitly, which ones are set in which process, when haproxy is started in
master-worker mode.
In addition, update examples in chapter "2.4. Conditional blocks". This might
bring more ideas for users how HAPROXY_* variables could be used in the
conditional blocks.
Since sd_notify() is now implemented in src/systemd.c, there is no need
anymore to build its support conditionnally with USE_SYSTEMD.
This patch add supports for -Ws for every build and removes the
USE_SYSTEMD build option. It also remove every reference to USE_SYSTEMD
in the documentation and the CI.
This also allows to run the reg-tests in -Ws with the new VTest support.
As mentionned by Thayne McCombs in #2728, it could be handy to have a sample
fetch function to retrieve the query string with the question mark
character.
Indeed, for now, "query" sample fetch function already extract the query
string from the path, but the question mark character is not
included. Instead of adding a new sample fetch function with a too similar
name, an optional argument is added to "query". If "with_qm" is passed as
argument, the question mark will be included in the query string, but only
if it is not empty.
Thanks to this patch, the following rule:
http-request redirect location /destination?%[query] if { -m found query } some_condition
http-request redirect location /destination if some_condition
can now be expressed this way:
http-request redirect location /destination%[query(with_qm)] if some_condition
Conditional blocks inherit the same tokenizer and argument parser as
the rest of the configuration, but are also silently concatenated
around groups of spaces and tabs. This can lead to subtle failures
for configs containing spaces around commas and parenthesis, where
a string comparison might silently fail for example. Let's better
document this particular case.
Thanks to Valentine for analysing and reporting the problem.
This can be backported to 2.4.
Spaces around commas or parenthesis in expressions are generally part
of the value due to the long history of supporting unquoted arguments.
But this tends to come as a surprise to new users and sometimes creates
subtly invalid configurations. Let's add some text covering this.
This can be backported to 2.4.
tasklet_wakeup_on() and its derivates (tasklet_wakeup_after() and
tasklet_wakeup()) do not support passing a wakeup cause like
task_wakeup(). This is essentially due to an API limitation cause by
the fact that for a very long time the only reason for waking up was
to process pending I/O. But with the growing complexity of mux tasks,
it is becoming important to be able to skip certain heavy processing
when not strictly needed.
One possibility is to permit the caller of tasklet_wakeup() to pass
flags like task_wakeup(). Instead of going with a complex naming scheme,
let's simply make the flags optional and be zero when not specified. This
means that tasklet_wakeup_on() now takes either 2 or 3 args, and that the
third one is the optional flags to be passed to the callee. Eligible flags
are essentially the non-persistent ones (TASK_F_UEVT* and TASK_WOKEN_*)
which are cleared when the tasklet is executed. This way the handler
will find them in its <state> argument and will be able to distinguish
various causes for the call.
These are user-defined one-shot events that are application-specific
and reset upon wakeup and were not documented. No backport is needed
since these were added to 3.1.
Contrary to what the doc states, it is not expected (nor relevant) to
use yield-dependent methods such as core.yield() or core.(m)sleep() from
contexts that don't support yielding. Such contexts include body, init,
fetches and converters.
Thus the doc got it wrong since the beginning, because such methods were
never supported from the above contexts, yet it was listed in the list
of compatible contexts (probably the result of a copy-paste), which is
error-prone because it could either cause a Lua runtime error to be
thrown, or be ignored in some other cases.
It should be backported to all stable versions.
Define a new QUIC congestion algorithm token 'cubic-pacing' for
quic-cc-algo bind keyword. This is identical to default cubic
implementation, except that pacing is used for STREAM frames emission.
This algorithm supports an extra argument to specify a burst size. This
is stored into a new bind_conf member named quic_pacing_burst which can
be reuse to initialize quic path.
Pacing support is still considered experimental. As such, 'cubic-pacing'
can only be used with expose-experimental-directives set.
Modify quic-cc-algo for better extensability of optional parameters
parsing. This will be useful to support a new parameter for maximum
allowed pacing burst size.
Take this opportunity to refine quic-cc-algo documentation. Optional
parameters are now presented as a list which would be soon extended.
Rename 'tune.quic.frontend.max-window-size' with the prefix 'default-'.
This highlights the fact that it is not a hard limit, as it can be
overriden if specifying an optional window size via quic-cc-algo on a
bind line.
No need to backport as this keyword was added on the current dev
version.
414-Uri-Too-Long and 431-Request-Header-Fields-Too-Large are now part of
supported status codes that can be define as error files. The hash table
defined in http_get_status_idx() was updated accordingly.
"show sess" command now supports a list of options that can be set after all
other possible arguments (<id>, all...). For now, "show-uri" is the only
supported option. With this options, the captured URI, if non-null, is added
to the dump of a stream, complete or now. The URI may be anonymized if
necessary.
This patch should fix the issue #663.
Historically, an agent-check program is only able to set a proportial weight
to the initial server's weight. However, it could be handy to also set an
absolute value. It is the purpose of this patch.
Instead of changing the current way to set a server's weight, a new
agent-check command is introduced. The string "weight:", followed by an
positive interger or a positive interger percentage, can now be used. If the
value ends with the '%' sign, then the new weight will be proportional to
the initially weight of the server. Otherwise, the value is considered as an
absolute weight and must be between 0 and 256.
This patch should fix the issue #360.
